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Nightmare · 06-20-07, 01:18 PM

Speed can be one of the hardest things to figure out, but it’s pretty straight forward with some practice. If you play with the map contact updates on (contacts on nav map updated for you) and using Imperial measurements (get the mod that fixes the mast height problem or run RFB or other mods that include it), here’s what worked for me. It does involve some math though so either be good at mental math or have a calculator handy.

Knots are a unit of speed for boats and planes. Knot means nothing more than nautical miles per hours. If a ship is traveling 15 knots, the boat is traveling 15 nautical miles per hour. Since there is 60 minutes in an hour, we can take an observation of a target between two points and measure the distance it takes to travel over a period of time.

First thing I do once I spot a target is get on an intercept course, then I start tracking to figure out speed. Go to the nav map and bring up the stopwatch. Take the mark tool and mark a point smack dab in the middle of the target, and immediately start the stopwatch. If you are submerged go ahead and lower the scope. Now all we do is wait for several minutes. How long to wait depends on how much time you think you have. Longer you wait, the more accurate the calculation will be. I typically use 6 minutes between observations, so I’ll use that in this example.

At around 5:45 on the stopwatch I start raising the scope and find the target again. Switch to the nav map and right at the 6-minute mark; mark the target in the dead center again. Lower the scope, and now it’s time to take the ruler and measure the distance between your two marks. The ruler is only accurate to a tenth of a nautical mile so you’ll have to eyeball if the distance is somewhere between. Let’s say I have about .55 nautical miles traveled between the two marks according to the ruler. Here the formula:

Speed = (60 / minutes between observations) x distance

So here is what it looks like in my example:

Speed = (60 / 6) x .55
or
5.5 = 10 x .55

I now have the speed of roughly 5.5knots (either round up or down accordingly) for this target. Go ahead and raise the scope and lock on the target. I’m assuming you already have the target identified with the correct masthead height entered, so go ahead and get your range, and send to TDC. Get your AOB either eyeballing it or the method DedEye listed above, and send to TDC. Now enter the speed, and send to TDC. Now click the button to activate the TDC (should turn red). Lower the scope, but occasional take a look.

On the TDC at the top there are two dials. The top most one is your target and the one below that is ownship (our ship). At the top of the dial of own ship there is a mark that if you hover the mouse over it, it’ll display the bearing that the TDC thinks the target should be at. If it matches what you see in the scope, your solution is still good. If it’s off by a wide margin, then the target has either changed course or speed. If thats the case, turn the TDC off and start the process again.

Once the range and impact angle look good and the TDC matches what you see go ahead and fire. I usually fire 3 torpedoes per target (just like most of the successful skippers did in the war) with 2 of the 3 having a slight offset. 90% of the time 2 of them will hit.

06-20-07, 01:18 PM	#32
Nightmare Engineer Join Date: Nov 2003 Location: Portland, OR Posts: 210 Downloads: 10 Uploads: 0	Speed can be one of the hardest things to figure out, but it’s pretty straight forward with some practice. If you play with the map contact updates on (contacts on nav map updated for you) and using Imperial measurements (get the mod that fixes the mast height problem or run RFB or other mods that include it), here’s what worked for me. It does involve some math though so either be good at mental math or have a calculator handy. Knots are a unit of speed for boats and planes. Knot means nothing more than nautical miles per hours. If a ship is traveling 15 knots, the boat is traveling 15 nautical miles per hour. Since there is 60 minutes in an hour, we can take an observation of a target between two points and measure the distance it takes to travel over a period of time. First thing I do once I spot a target is get on an intercept course, then I start tracking to figure out speed. Go to the nav map and bring up the stopwatch. Take the mark tool and mark a point smack dab in the middle of the target, and immediately start the stopwatch. If you are submerged go ahead and lower the scope. Now all we do is wait for several minutes. How long to wait depends on how much time you think you have. Longer you wait, the more accurate the calculation will be. I typically use 6 minutes between observations, so I’ll use that in this example. At around 5:45 on the stopwatch I start raising the scope and find the target again. Switch to the nav map and right at the 6-minute mark; mark the target in the dead center again. Lower the scope, and now it’s time to take the ruler and measure the distance between your two marks. The ruler is only accurate to a tenth of a nautical mile so you’ll have to eyeball if the distance is somewhere between. Let’s say I have about .55 nautical miles traveled between the two marks according to the ruler. Here the formula: Speed = (60 / minutes between observations) x distance So here is what it looks like in my example: Speed = (60 / 6) x .55 or 5.5 = 10 x .55 I now have the speed of roughly 5.5knots (either round up or down accordingly) for this target. Go ahead and raise the scope and lock on the target. I’m assuming you already have the target identified with the correct masthead height entered, so go ahead and get your range, and send to TDC. Get your AOB either eyeballing it or the method DedEye listed above, and send to TDC. Now enter the speed, and send to TDC. Now click the button to activate the TDC (should turn red). Lower the scope, but occasional take a look. On the TDC at the top there are two dials. The top most one is your target and the one below that is ownship (our ship). At the top of the dial of own ship there is a mark that if you hover the mouse over it, it’ll display the bearing that the TDC thinks the target should be at. If it matches what you see in the scope, your solution is still good. If it’s off by a wide margin, then the target has either changed course or speed. If thats the case, turn the TDC off and start the process again. Once the range and impact angle look good and the TDC matches what you see go ahead and fire. I usually fire 3 torpedoes per target (just like most of the successful skippers did in the war) with 2 of the 3 having a slight offset. 90% of the time 2 of them will hit. Last edited by Nightmare; 06-20-07 at 03:04 PM.